Flow fields for distribution of fluids in electrochemical cells are described in numerous references. A number of references depict flow fields having serpentine channels, including: U.S. Pats. Nos. 4,631,239; 4,686,159; 4,853,301; 4,988,583; 5,108,849; 5,252,410; 5,683,828; 5,750,281; 5,773,160; 5,846,668; 5,858,567; 5,858,569; 5,922,485; 5,945,232; 6,071,635 and 6,099,984. A number of references depict flow fields having multiple interleaved serpentine channels, including: U.S. Pats. Nos. 5,683,828; 5,750,281; 5,773,160; 5,804,326; 5,840,438; 5,858,567; 5,998,055; 6,071,635 and 6,093,502. A number of references depict interdigitated flow fields, including: U.S. Pats. Nos. 5,252,410; 5,641,586 and 6,207,312. In an interdigitated flow field, channels having an inlet but no outlet alternate with channels having an outlet but no inlet. U.S. Pat. No. 5,686,199 depicts a flow field having a series-parallel arrangement of channels. U.S. Pat. No. 6,048,634 depicts flow field patterns wherein pairs of adjacent channels carry flow in opposite directions, including spiral patterns and serpentine patterns. In addition, the use of a metal screen as a flow field has been taught, e.g. in U.S. Pat. Nos. 4,855,193; 5,798,187; 6,037,072 and 6,207,310.
U.S. patent application Ser. No. 9/430,568 discloses a flow field for an electrochemical cell having microflow channels of specified width, depth, and/or pitch, which may additionally comprise micro-features within the channels.
U.S. patent application Ser. No. 9/954,601 discloses a flow field for distribution of fluids that provides uniform lateral flux of fluids across the land areas of the flow field. In one embodiment, the flow field comprises a serpentine channel that comprises non-parallel sequential major segments.
EP 1 184 923 A2 discloses a flow field comprising channels having a draft angle greater than 0 degrees, preferably at least 7 degrees, and more preferably between about 7 degrees and about 15 degrees.
U.S. Pat. No. 4,292,379 describes flow fields on either side of a bipolar plate wherein the depth and/or separation of parallel channels are varied so as to create an uneven distribution that matches the uneven distribution created by the opposing face of the plate.